Manufacture of incandescent gas mantles



Patented Nov, 21, 1922.

i i J F gi *JOHN PHILPOTT HENRY SUPER, OF LEYTON, LONDON, AND THOMAS TERRELL, JR 011 IMUSWELL HILL, LONDON, ENGLAND, .ASSIGNQRS Of? ONE-THIRD TO THOMAS TER- RELL, OF LONDON, ENGLAND.

MANUFACTURE OF INCANDESCENT GAS IYIANT-LES.

N0 Drawing.

1 0 all whom it may concern:

e it known that we,.Joi1N PHILPOTT HENRY tjornn, residin in Leyton, London, England, and THOMAS FERRELL, Jr., residing in Muswell Hill, London, England, both subjects of the King of England, have invented certain new and useful lmprovements in the Manufacture of Incandescent Gas Mantles, of which the following is a specification.

This invention is for improvements in the manufacture of incandescent gas mantles and is particularly applicable to the manufacture of mantles of the kind known in the trade as soft, that is to say mantles which are sold in the unincinerated condition. It may, however, also be used in the manu facture of hard mantles.

Soft mantles have hitherto been produced by dipping the fabric into a solution of the nitrates of thorium and cerium, and drying the same. After drying them, they may be treated with ammonia to convert the nitrates of thorium and cerium into hydroxides. In this case the fabric is thoroughly washed to free it from nitrate of ammonia or other impurities and then dried, leaving an organic tissue containing the oxides, or hydrated oxides of thorium and cerium.

The mantle which has been thus formed is prepared for use by burning out the material of the fabric. In all cases a considerable shrinkage of the impregnated fabric occurs, firstly during the burning out of the cellulose, and secondly in the shaping and seasonin process.

We have ound that if, instead of con verting the nitrates of thorium and cerium into oxides, they are converted into fluorides, or fluorides admixed with oxides, the mantles thus produced have a less tendency to shrink while burning off than the simple oxide-impregnated mantles described above. Moreover, these mantles containing the fluorides are more efficient in that they give a greater emission of light for the same consumption of gas than do the mantles containing the oxide.

The best method at present known to us for carrying the present invention into practice is as follows :The knitted fabric of a mantle is made from artificial silk (hydrocellulose), and it is first soured in dilute acid, thoroughly washed and dried. It is Application filed July 25, 1321. Serial No. 487,410.

then dipped into a solution of the nitrates of thorium and cerium prepared in the usual manner and dried, preferably in warm air at a temperature of say 90 F.

A 10% solution of sodium fluoride is prepared, this solutionbeing pure and neutral to the same extent as the sodlum fluoride is commercially sold. A small quantity of ammonia is added to this solution to make it slightly alkaline, a proportion which has been used bein two parts in a thousand, and into the sofution thus rendered alkaline thedriedimpregnated fabric is dipped. The action of the sodium fluoride is to precipitate the fluorides of thorium and cerium into the artificial silk, and there is also present a small percentage of oxides of thorium and cerium. The fabric is then thoroughly washed to remove substantially all the soda which may be present as fluoride, nitrate and sulphate, and is dried, preferably in a current of warm air, and made up into mantles in the ordinary way. The-mantles produced in this manner may be sold as soft mantles, or they may be burned off in the factory and sold as the ordinary hard mantles.

It is preferred to use artificial silk as the fabric of the mantle, but cotton, preferably mercerized, or ramie may also be used, although these mantles may not be so satisfactory as the artificial silk mantles.

e have found that instead of the sodium fluoride, potassium fluoride may be used with equally good results. It is also possible to use iron fluoride to attain the desired result, but owing to the difliculty of removing the iron from the mantle, thi is not commercially practicable.

Incandescent gas mantles which have been manufactured in the manner hereinbefore described have the important advantage that the shrinkage and deformation ordinarily obtained in the process of burning them off is absent or substantially so, and this is of particular advantage in the case of soft mantles which are burned off by the consumer, on the burner on which the mantle is to be used, since it is not necessary to effect theburning off in two stages as is ordinarily supposed to be done. An ordinary soft mantle should be ignited and burned ofl completely before the gas is turned on, but

if the user does not follow out this process the mantle will probably be distorted and liable to break, whereas with mantles manufactured according to the present invention, since there is little or no shrinkage or distortion, the burning-off operation may be effected in a single stage without causing deterioration of the mantle.

What we claim as our invention and-desire to secure by Letters Patent is:

1. 1-'L process for themanufa'cture of 1ncandescent gas mantles, in which the fabnc is impregnated with a solution oft-he illu-' is impregnated with a solution of the'illuminating salts, dried, treated with a solution of the fluoride 01 sodium or potassium, and then washed and dried, substantially as described.

3. Incandescentgas mantles comprising a fabric of artificial silk which has been impregnated with a solution of nitrates of thorium and cerium, dried, treated with a 'solution'of fiuoride'of sodium or potassium,

wvashed, and dried, substantially as described. I

In testimony whereof we have signed our names to this specification.

JOHN PHILPOTT HENRY sores. THOMAS TERRELL, JR. 

